Okay, I am stopping before I make this any worse. After I welded in the two back cab lower patches I seem to have gotten it too hot and caused a large section to oil can. Most of this will be hidden behind the bed front but I still think it should be addressed. I tried the heating up and rapid cooling with a small torch in a few areas which fixed one spot but now seems like it created a bigger one which I've stopped at before I really mess this up.

Searching old threads someone mentioned using panel adhesive and gluing a large piece of sheet metal to the inside of the cab to stiffen it up. Is that a good option? Not sure of anyone skilled in my area to even look at this or what else I can safely try.

Ay suggestions welcome.
Thanks,
Matt

 

Shrink disk is like a torch it just cover more area and not as hot unless you leave it there to long. How bad is the oil canning I mean are you going to do body work there or just sand it and paint it. I have a roof of a 68 Ford truck oil canning got most of it out with shrinking disk then I did what you did heated up little areas that were the worst and cooled them until I got most of the oil canning out but it still does it if you real push down on it so doing body work is sort of a pain in the a** because you can't apply to much pressure. Yes gluing another piece of sheet metal behind will double wall it and stop the oil canning but it has to be tight up against it if there voids in the glue you find the same thing.

 

When you weld a seam the metal expands then the weld shrinks as it cools. It shrinks more than it has expanded, so you need to stretch out the metal next to the weld. You need to planish the weld if possible. If you can get at it, hammer the weld with a dolly behind it.
Since you have already used heat, you may have dug your self deeper.....
Kinda hard to diagnose over the net......got any pics?

 

A shrinking disk won't help with an oil can. They work pretty good to smooth an area that's been hammered on haphazardly (bag of walnuts syndrome). Tinman has it right, but as he says it's hard to explain exactly what to do without seeing it. If the oilcan is in the panel you installed the weld seam likely need stretching, but how sucessful that will be depends on how it was welded. Common mig wire is too hard to stretch and will likely crack, flux core wire is worse yet. That's why I highly recommend using nothing but ESAB "East Grind" wire for mig welding body metal. It is much softer than other wires. Read my MIG welding tutorial:
https://www.ford-trucks.com/forums/1...-practice.html

I have written a lot of metal working how tos on here. Do an advanced search on my user name in this forum using body work, welding, heat shrinking, as key words.

 

Sometimes one just gets deeper & deeper making it worse. Rear of cab
oil canning a typical case where as I get the oil can out of it with props sticks
anything so its straight, from the inside "other side" It gets a nice coat of
body filler. And sprayed with a little undercoat, most of the gas tank covers that
up. Another good case is a hood.

 

Filling over an oilcan is never a good idea. When the weather changes the panel will expand/contract and likely pop the oilcan, making the filler bulge and/or crack. Let's see what you have before you go any further and make it worse. Adding a brace across only ends up making two smaller oilcans out of it.

 

I tried to get a picture but getting a good angle that shows it is not working out. I messed with it some more, which I wasn't going to do, and now I have a small section about 3" in diameter right above the cab corner that I can push in. When pushing that in, a large section in the center lower cab wall (about 12" in diameter) pops out. Vice versa happens when pushing in on the large section. The small area that separates the two sections is the one I heated before starting this thread.

My concern with the filler is cracking. Obviously most of this will never be seen once the bed is on, but I just want to get it right. Ax, yes I have been using the mig welding wire from Home Depot. You've got some great info posted on that tutorial...thanks for the link.

I will try again with a picture...I know describing it is not the best help to get a solution.

 

just take a picture of the whole panel, I need to see where your weld seams are. Draw around the oil cans with a sharpie or permanent marker (will wash off with alcohol) Do you have a helper who can hold a dolly on the inside? Get a spool of the 0.025 Easy grind wire before you do any more welding. You can use it for general purpose welding as well, I use it for all my welding.. It is usually difficult to find locally, online source in tutorial.

 

See my posts # 53, 55, 57 in this topic for more info on fixing oilcans: https://www.ford-trucks.com/forums/1...he-ugly-4.html

 

This is what I have. Both are circled with a black sharpie

 

Ok, looks like the patch likelygoes around the corner. The seam shrinkage pushed the corner towards the center, making the rear panel too large for the area. Think about what would happen if you put a giant clamp on both cab corners and squeezed, The right thing to do is to stretch the seam across the top of the patch so it would grow in length, moving the corner outwards. Think what happens if you roll a wad of dough or clay with a rolling pin, it grows in length. to do that you would need a helper that could hold and move a dolly in rythm with your hammering on the outside. See how to remove an oilcan method 1. post 53 in the hood topic linked above.
Te other alternative is to heat shrink the oversized area. If you don't have a helper then you're going to have a problem here as well since you still need to get a dolly behind the point you heat to do the shrink properly. Here's a couple hints tho: Never do two shrinks closer than 12" apart. A heat shrink when done correctly (see post # 55 in the hood topic)will shrink and tighten the metal for 12-18" around it. If done correctly the large oilcan area should take no more than two or three shrinks at most to remove, the small one just one. Doing a bunch of shrinks too close together doesn't do anything but make a bunch of lumps and bumps.

 

Thanks for the help. I will read up on this tonight and start fresh tomorrow afternoon when I get home. Hopefully I'll be able to post back with some positive progress!

 

Remember, When heat shrinking it is critical to lock in the shrunken metal by tapping the blister down, but as the heat spreads out across the panel (which it does pretty quickly < 10 sec after the blister forms.) the metal starts to expand rather than pull in. The blister is very soft, the dolly is there to keep the hot metal from being pushed back, use a VERY LIGHT tap!
Using the right tools is also important! Your body hammer should have at least a 1.5"-2" diameter face, and both the hammer face and the dolly needs to have a shallow domed face. If the hammer face is flat, you have the wrong hammer! If it is flat, you can either buy a correct hammer, a quality body hammer like a Martin is only about $10-15 more than a garbage one from a discount tool store. Shop for your body tools on ebay, a used quality hammer is about the same price as a piece of junk. Look for body hammers with handles with slender necks and oval or octagon shaped grip area. Ths gives good balance and helps you know if the face is facing the right way without looking when you pick it up. You are not driving nails or beating the panel into submission so you don't need a heavy handle! Hold the hammer near the end of the handle with a soft grip, and the index finger should be extended down the back of the hammer like you are pointing at the spot where you are going to tap the metal. The wrist stays locked and you lift and swing from the elbow. The upper part of the arm stays attached to the side of the body. This gives you a straight repeatable swing so the hammer hits exactly where needed, not haphazardly. This allows you to use ON DOLLY or OFF DOLLY hammer taps as needed. If you don't know the difference, learn it before doing any more work. Using the wrong technique is the main reason novices find body work difficult and make a mess!

 

Ax, thank you so much for taking the time to help guide me through this. Worked on it tonight with help from the wife and have most all of it taken care of. There are just two more small spots that have some play in them but overall it is much better than a few days ago. Hopefully tomorrow afternoon we will have it ready to go to the blaster and then epoxy primer.

Thanks again,
Matt

 

Matt, do two more shrinks, one each in the center of the flexible areas. This is quite common when shrinking out an oilcan. It's called chasing the shrink. That's why stretching the weld seam is the preferred method it's much easier to control.